1. Field of the Invention
The invention relates to a television image receiving apparatus and a CRT (Cathode-Ray tube)display apparatus which are equipped with an anode current detecting resistor connected between a ground side terminal of a secondary coil wound around a flyback transformer and generating a high voltage for an anode of a CRT and a power route with a predetermined voltage, and more specifically, relates to a television image receiving apparatus and a CRT display apparatus, which stop generation of a high voltage when a route of the high voltage has not yet connected.
2. Description of the Related Art
In production lines of television image receiving apparatuses, in the vicinity of an end of a process of the line, a commercial power source is supplied to a set to which, attachment of a substrate and a CRT etc., on which a flyback transformer is mounted, is completed so as to have it operated, and various inspections are to be carried out. On one hand, at the side of the set, when supply of the commercial power source is started, a high voltage generation circuit carries out such an operation that it generates a high voltage for an anode, and outputs the same (regarded as first related art).
Such related art that, in case that a connector of a deflection coil has not yet connected, an operation of a horizontal deflection circuit and an operation of a high voltage generation circuit are stopped, has been proposed (regarded as second related art). That is, by this technology, in order to detect a connection trouble between an output terminal of the horizontal deflection circuit and a deflection yoke, disposed is an abnormal voltage detection part. And, when the abnormal voltage detection part detected the connection trouble, supply of power to a horizontal oscillation part is stopped, and thereby, an operation of the horizontal deflection circuit and an operation of the high voltage generation circuit are made to be stopped (see paragraph [0027] in JP-A-9-247488). Or, when the abnormal voltage detection part detected the connection trouble, a signal from the abnormal voltage detection part is guided between the horizontal oscillation part and a horizontal drive circuit, and thereby, an operation of the horizontal deflection circuit and an operation of the high voltage generation circuit are made to be stopped (See paragraph [0028] in JP-A-9-247488). On this account, in case that a connector for a deflection coil is unconnected, an operation of the horizontal deflection circuit and an operation of the high voltage generation circuit are to be stopped (e.g., see, JP-A-9-247488).
A related art technology as shown below has been proposed (regarded as third related art). That is, by this technology, when discharge is generated at a high voltage portion, a noise is superposed on a horizontal oscillation pulse, and therefore, this noise is cut out by use of a zener diode. Also, a noise component which is cut out is rectified by a diode, and stored up in a capacitor. And, it is designed in such a manner that, when a voltage between terminals of the capacitor reached to a certain level, it is judged as a discharge. In addition, in this judgment, distinguished are such a fact that the discharge is continuing more than a predetermined amount of time, and such a fact that it is simply an instantaneous noise. And, in case of a noise which continues for more than a predetermined amount of time, it is judged as a discharge to stop supply of power (e.g., see JP-A-10-65931).
However, in the first related art, even in case that an anode cap is not connected to an anode of a CRT, or an anode ground is not connected to ground, the high voltage generation circuit generates a high voltage. On this account, in case that the anode cap and the anode ground have not yet been connected, there is such a case that a discharge occurs between them and a unexpected spot, so that there occurs such a risk that a set is broken down. Furthermore, there is such a risk that an inspector gets an electric shock, which is very dangerous. And, the such like situation also occurs at the time of repairing a substrate, in the same manner. On this account, in case that a route of a high voltage is unconnected, such a configuration that an operation of a high voltage generation circuit is made to be stopped by detecting to be unconnected has been desired.
The second related art is configured in such a manner that, in case that a connector of a deflection coil becomes unconnected, an operation of a horizontal circuit and an operation of a high voltage generation circuit are stopped. However, an operation in case that a route of a high voltage for an anode became unconnected is not described at all. On this account, in case of an objective which is desired in the first related art, i.e., in case of stopping an operation of a high voltage generation circuit when a route of a high voltage becomes unconnected, it is a technology which is difficult to be applied.
The third related art is of such a configuration for detecting a discharge of a high voltage. On this account, in case of an objective which is desired in the first related art, i.e., in case of stopping an operation of a high voltage generation circuit when a route of a high voltage becomes unconnected, it is a technology which is difficult to be applied.